Relevant thread: A fair coin is flipped 2k times. What is the probability that it comes up tails more often than it comes up heads?

Yesterday I answered a question by giving a simple hint. The question was nothing special (in fact, it was a duplicate) and neither was my answer. To my surprise, I come back today and see +200 on my reputation from this answer (it received 28 upvotes).

Does anyone have an idea as to why this question got so much attention? What's weird is that the attention only came in the way of views and votes. It's not like the question sparked a large debate about the subject matter or provided many answers approaching the problem in different ways. It seems like any other ol' homework problem, except with more votes. Can anyone comment on what happened here?

  • 7
    $\begingroup$ I think I recall this question getting onto the hot network questions list; these tend to have somewhat bizarre voting behaviour since there's a lot of votes from people from other SE sites. $\endgroup$
    – user61527
    May 22, 2014 at 5:18
  • $\begingroup$ The same thing happened to me a while ago. The only thing I could figure out was that the question was on the Hot Network Questions list. Voting is capricious. $\endgroup$
    – robjohn Mod
    May 22, 2014 at 10:05
  • 26
    $\begingroup$ It's the gods of Stackexchange Karma evening your score for that really clever answer you posted two weeks ago that still has 0 upvotes. $\endgroup$
    – MJD
    May 22, 2014 at 13:12
  • $\begingroup$ Voting is hard to predict, even in hindsight. I obtained one of my "Great Answer" gold badges for a short answer (essentially: "vacuosly true") to a correspondingly trivial question, whereas another (just as short and unavoidably almost identical) answer by another user to the same question from almost the same point of time received "only" 10 points - I meanwhile take more pride in less rewarded answers (cf. last paragraph of Goos's answer) $\endgroup$ May 23, 2014 at 17:11
  • $\begingroup$ I would say that it's mostly the hot question effect, however, it also has to do how accessible the question and answer is. My current two top-voted answers are examples of this too. $\endgroup$
    – dtldarek
    May 23, 2014 at 17:36
  • 2
    $\begingroup$ Related: Sometimes I don't get why people upvote some answers so much. In one comment there, I recount the story of some mundane answer of mine that currently stands at +14, and sum up the reason why: “I was lucky”. $\endgroup$
    – MJD
    May 25, 2014 at 5:38
  • $\begingroup$ This is actually one of the motivations for the +200 reputation cap. Popular questions spread around easily, and the best way to mitigate the effects is to cap daily reputation gain. $\endgroup$
    – user66698
    May 29, 2014 at 23:44
  • $\begingroup$ There's always the Batman equation: math.stackexchange.com/q/54506/27978... $\endgroup$
    – copper.hat
    May 31, 2014 at 2:25
  • $\begingroup$ math.stackexchange.com/questions/542808/… is another question of same kind... :D $\endgroup$
    – user87543
    Jun 4, 2014 at 14:05

1 Answer 1


This has happened to me several times. Alas, there is no way to see who exactly the upvotes are from, so there is no way to tell for sure. But, note:

  • Your question has 1475 views, as of this writing. More views $=$ more upvotes, period, even on a mediocre question.

  • Your question is about a well-known topic, and people upvote things they understand. It is a well-known phenomenon on mathSE that more advanced questions and answers get less attention simply because less people follow the topic of those questions.

  • People don't necessarily refrain from upvoting just because the question is a duplicate.

  • Upvotes don't always come from established mathematicians or mathSE users. In fact many users from other SE sites come and generate a lot of uninformed votes (exhibit A).

With regards to the first bullet point, where did all those views come from? Well, probably from the users from other SE sites, see bullet 4. In particular, what often happens is:

  1. The "Hot Network Questions" list attracts views from users outside of mathSE, from the SE network in general.

  2. The association bonus allows these users to vote, even if they are completely uninformed about math or about the customs on mathSE.

This has become a significant problem on MathOverflow (1, 2) as well, but the proposed solution here (which I have upvoted) has mixed feedback. The problem is that votes are simultaneously serving two conflicting roles. On the one hand, votes are supposed to indicate how good or valid a question or answer is, in which case we only want established users to cast them. On the other hand, votes indicate that an answer is helpful or that it solved a person's problem, in which case we want any average user (i.e. a user trusted on some site in the SE network) to be able to express that an answer was helpful.

In general, I would not expect the vote total on any of your answers to accurately reflect whether the answer is good or not, except in the case of low vote totals like +1, +2, -1, -2. This proposal for example tries to address this. See also: If you worry too much about voting patterns on this site, you will lose your sleep.


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